De Broglie Wavelength Calculator
Choose the particle and enter its speed.
Your numbers
Your results
Wavelength (m)
Wavelength (m)
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Wavelength (nm)
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Momentum (kg·m/s)
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Lorentz factor γ
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De Broglie Wavelength Calculator by TheCalcTools
How the De Broglie Wavelength Calculator works
Louis de Broglie proposed that every particle has a wavelength λ = h/p, where h is the Planck constant and p the momentum. This wave nature lets electron microscopes resolve atoms.
Momentum here is relativistic, p = γmv, which matters above about 10% of the speed of light. Everyday objects have wavelengths far too small to notice.
The formula
λ = h ÷ p, p = γ m v
Worked example
Using the default values shown in the calculator:
| Particle | Electron |
|---|---|
| Mass (kg) | 0.145 |
| Speed (m/s) | 1e+06 |
- An electron at 1,000 km/s has a wavelength of 0.7274 nm.
Result:
| Wavelength (m) | 7.27385e-10 |
|---|---|
| Wavelength (nm) | 0.7274 |
| Momentum (kg·m/s) | 9.10943e-25 |
| Lorentz factor γ | 1.0000 |
Frequently asked questions
What is the wavelength of a baseball?
A 0.145 kg ball at 40 m/s has λ ≈ 1.1 × 10⁻³⁴ m, far smaller than any atom.
Sources and further reading
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This calculator gives estimates for information only. Check important results independently before you rely on them. See our disclaimer.